It’s All About the Outputs

Inputs are nice to look at, but if you’re not turning on outputs, you’re not doing anything.

A control system is only as good as the input/output (I/O) attached to it. The I/O is the pipeline to instrumentation in the field and is how the control system visualizes and manipulates the process.

You can’t monitor anything that you’re not reading an input from. Likewise, you can’t control anything that an output isn’t attached to.

I’ve had customers that wanted me to control something in a nether region that wasn’t covered by I/O. So, a lot of time would be spent developing some flaky configuration that inferred information from inputs adjacent to the nether area. Then, it would manipulate something in that area by turning on nearby outputs to influence it. This wasn’t a good idea then and it still isn’t now. If the same amount of time and money would have been spent installing a couple of instruments in the field and wiring them to the rack room, the problem would have been solved the correct way.

With that being said, you can actually take “It’s all about the I/O” and break it down further to “It’s all about the outputs.”

Inputs are nice to look at. People like to trend them, totalize them, and put them on graphics and dashboards. Inputs are also needed to know when to turn on some of the outputs. You can have process graphics full of inputs to gaze at all day. But, if you’re not starting pumps or opening valves, nothing is ever going to be produced. You can’t build a house by looking at a pile of 2×4 studs. At some point, you have to pick up a hammer and start pounding nails. So, it all boils down to the outputs. If you’re not turning on outputs, you’re not doing anything.

This also applies directly to your work in general. Are you turning on outputs? What have you produced lately? Are you (a) knocking items off that project task list like a metal machine, (b) having meetings with the heads because each of you like to hear yourself talk, or (c) watching Ren and Stimpy videos in the office? Pop quiz: only one of those activities involve turning on outputs. Which one is it?

Now, go turn on some outputs.

This post was written by Jay Griffin, PE. Jay is a principal engineer at MAVERICK Technologies, a leading automation solutions provider offering industrial automation, strategic manufacturing, and enterprise integration services for the process industries. MAVERICK delivers expertise and consulting in a wide variety of areas including industrial automation controls, distributed control systems, manufacturing execution systems, operational strategy, business process optimization and more.